The present inventon relates generally to barriers for preventing vehicles from travelling along predetermined paths although it is understood that the invention has applicability to similarly controlling pedestrian traffic as well.
More particularly, the present invention constitutes an improvement in vehicle barriers of the general type disclosed in applicant's U.S. Pat. No. 3,968,596. Such vehicle barriers include an upright support means situated beside the path of travel of a vehicle, e.g., at the entrance to a parking space, and an elongated barrier arm having a blocking position when it projects laterally from the upright support means across the path for preventing the vehicle from travelling past the barrier arm along this path when the barrier arm is in its blocking position. A connecting means connects the barrier arm to the upright support means for swinging movement with respect thereto about a substantially horizontal axis between the blocking position extending across the path and a non-blocking position where the barrier arm extends substantially vertically along the upright support means to permit a vehicle to travel along the path. In particular the connecting means connects the arm to the support means for swinging movement in an upward direction from the blocking to the non-blocking position and in a downward direction from the non-blocking to the blocking position. Moreover, the axis around which the arm swings is situated at a region of the lower end of the arm when the latter is in its non-blocking position.
Such vehicle barriers are advantageous in that the barrier arm may be relatively long yet be easily swingable between its blocking and non-blocking positions without requiring exertion of relatively large forces so that any individual, even though not particularly strong, can easily swing the barrier arm between its blocking and non-blocking positions. The fact that the barrier arm can be considerably longer than, for example, arms of vehicle barriers of the type wherein the arm is pivoted at its end to an upright support and is swingable upwardly to the blocking position, makes it possible to use such vehicle barriers in a variety of different applications, such as at the entrance to a large parking area in order to prevent unauthorized vehicles from entering into the parking area. Moreover, the upright support means of such vehicle barriers can be relatively slender and short resulting in considerale savings in material costs.
It has been found, however, that the vehicle barriers of the general type disclosed in U.S. Pat. No. 3,968,596 are not always entirely satisfactory. More particularly, the upright support means from which the elongated barrier arm projects has the construction of an I-beam which is generally embedded in the ground on which the vehicle travels. Thus, in cases where an existing upstanding structure, such as a wall or a column, is situated adjacent to the entrance to the path of travel of the vehicle, it has been necessary to embed the upright support means in the ground adjacent to the wall or column thereby taking up a valuable three or four inches of clearance space which would otherwise be available and through which the vehicle could pass. In cases where space limitations are critical, e.g., where a parking space provides a minimal clearance between the wall or column situated at its entrance, the provision of an I-beam embedded in the ground next to the existing structure, even when placed as close as possible thereto, still eliminates valuable clearance space making it that much more difficult for an authorized vehicle to nevigate into the parking space. The use of I-beams as upright support means aggravated this problem to some extent in that the side walls constituting the same are relatively long thereby taking up even further valuable clearance space.
Another problem presented by the vehicle barriers of the type disclosed in the above-mentioned patent is that when the barrier arm is in its blocking position and is impacted against by, for example, an unauthorized vehicle attempting to travel past the same, it is possible that the vehicle barrier will be subjected to serious structural damage. Since the upright support means is embedded in the ground and the barrier arm is pivoted thereto about a horizontal axis, the application of a force to the barrier arm tending to push the arm around the upright support means will tend to stress and possibly break or deform the various components.